by Wen Tsui
LOS ANGELES, Jan. 13 (Xinhua) -- A new study on climate volatility sheds light on the devastating wildfires currently raging across U.S. Los Angeles County.
The research, published last week in Nature Reviews Earth & Environment, explains how global warming intensifies both wet and dry extremes, creating ideal conditions for fast-moving, destructive fires -- such as the Palisades and Eaton blazes.
The study, titled "Hydroclimate Volatility on a Warming Earth," reveals that rapid transitions between extremely wet and extremely dry conditions are becoming more frequent and more intense due to climate change. Such volatility fosters a dangerous cycle: abundant vegetation flourishes during wet periods, becoming highly combustible fuel in subsequent dry spells.
"Hydroclimate volatility refers to sudden, large, and/or frequent transitions between very dry and very wet conditions," said lead author Daniel L. Swain. The research indicates that globally averaged subseasonal (three-month) "whiplash" events have increased by 31 percent to 66 percent since the mid-20th century.
This climate whiplash effect is evident in the current Los Angeles wildfires. The region experienced heavy rainfall earlier in the year, encouraging widespread vegetation growth. However, hot, dry conditions soon followed, converting that vegetation into prime fuel. Powerful Santa Ana winds then accelerated the fire's rapid spread.
Santa Ana winds are strong, hot, and exceedingly dry, typically affecting Southern California in the fall and winter. These winds form when high-pressure systems over Nevada and Utah push cold, dry air through mountain passes and canyons toward the California coast, warming the air significantly as it descends.
Wind speeds can exceed 70 miles per hour, quickly parching vegetation and increasing fire risk.
According to the California Department of Forestry and Fire Protection (Cal Fire), the Palisades Fire, which ignited on Jan. 7, has already burned 95.75 square kilometers and is only 14 percent contained. Meanwhile, the Eaton Fire has consumed over 57 square kilometers and destroyed 7,000 structures.
The speed at which these fires spread aligns with the study's projections.
"With 3 degrees Celsius of warming, subseasonal whiplash is projected to increase by 113 percent over land areas," said Swain. This heightened volatility can lead to more frequent and intense wildfires, as the current Los Angeles blazes demonstrate.
The study also shows how climate change amplifies wet and dry extremes.
Rising temperatures boost the atmosphere's water-holding capacity, leading to more intense rainfall events. Simultaneously, higher temperatures accelerate evaporation rates, drying out vegetation more quickly.
These dual effects were displayed in Southern California during the 2022 to 2023 season when Downtown Los Angeles received 613 millimeters of rain -- 308 millimeters above the seasonal average.
By early January this year, however, Los Angeles International Airport had recorded only 0.8 millimeters of rainfall since Oct. 1, 2024, a stark contrast to the previous wet season.
Regions at high latitudes and those stretching from northern Africa through South Asia are expected to experience the greatest increases in hydroclimate volatility. Such shifts can exacerbate natural hazards -- flash floods, wildfires, landslides, crop losses, and disease outbreaks -- and cause substantial disruptions to both societies and ecosystems.
The review stresses that conventional water management, which typically separates flood and drought planning, is increasingly inadequate. Instead, it advocates for adaptive, integrated strategies -- such as nature-based solutions -- that account for both extremes and proactively secure water supplies.
Given these findings, the implications for fire management and urban planning are significant. As climate volatility worsens, communities in fire-prone areas may need to reevaluate their preparedness and response strategies.
Many fire hydrants went dry during the battle against the Palisades Fire, forcing firefighters to withdraw; the lack of water contributed to extensive home losses. This crisis exposed a critical gap in the Los Angeles metropolitan area's water infrastructure and planning.
The research underscores the urgent need to confront climate change and its far-reaching effects on extreme weather.
Without substantial cuts in greenhouse gas emissions, the frequency and intensity of climate-driven disasters -- such as the Palisades and Eaton fires -- will likely continue rising in the years ahead.
